Marylaxd Geological Survey 199 



" Calyx deep, sides thin and nearly erect; a flat space at the bottom. In 

 one calyx, having a diameter of 20 mm., there are fifty-four lamellae; 

 alternate lamellae extending only a short distance from the walls at the 

 base of the calyx and frequently coalescing with the primary lamellae. 

 For some distance below the calyx-margin the lamellae are of the same 

 size, their edges smooth and rounded, becoming sharp below, and their 

 sides often distinctly granulose or spinulose. The primary lamellae unite 

 and coalesce at the center of the calyx, forming an indistinct plate or 

 vesiculose core from 3 to 5 mm. in diameter. Fossette obscure or obsolete. 

 This species is distinguished by the usually rigid straightness of its form, 

 and the strongly ribbed exterior." Hall, 1887. 



Length, 25 mm. ; diameter of calyx, 16 mm. 



The specimens observed agree fully with those described by Hall from 

 New York. 



Occurrence. — Helderberg Formation, Nevt Scotlaxd Member. Cor- 

 riganville, Maryland. Abundant at Cherry Kun, West Virginia. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



Streptelasma cumberlandica n. sp. 

 Plate XVIII, Figs. 1, 2 



Description. — Corallum simple, conical, curved, enlarging regularly in 

 diameter from apex to calyx. Annulated by shallow constrictions, striated 

 longitudinally by septal furrows. Calyx not observed. Septa about 130 

 in number, alternating in length. Some of primary septa unite in center 

 to form a pseudo-columella. Secondaries varying in length, their average 

 length nearly half that of primaries. Tabulae present but apparently few. 



Length, 75 mm. ; diameter of calyx, 50 mm. 



Two specimens have been observed which appear distinct from any 

 previously described species. The smaller of these is much less curved 

 than the specimen figured. 



Occurrence. — Helderberg Formation. Near Cumberland, the precise 

 locality and horizon being unknown. 



Collection. — Mar}dand Geological Survey. 



